Punch press with improved slug handling system

ABSTRACT

A punch press includes a bin mounted below a die and communicating with the latter by way of a passage which directs slugs punched from the workpiece into the bin. A vacuum source is connected to a pipe leading from the bin and draws the slugs through the passage and into the bin. Mounted beneath a door in the bottom of the bin is a power operated conveyor for transporting the slugs away from the bin. The door may be opened automatically during an interruption in the punching operation of the press whereby the slugs are dumped onto the conveyor after the latter is actuated to carry the slugs away from the bin. During the punching operation, refrigerated air and lubricant are forced under pressure into a chamber defined by a stripper housing which encloses the punch, the lubricant and the air forming a mist for cooling the punch. As the mist escapes from the chamber through an opening in the stripper, it is drawn into the die by the vacuum and thus also cools and lubricates the die. Excess lubricant is drawn through the bin into the pipe and is separated from the air by a filter at the discharge end of the pipe before the air is exhausted into the atmosphere.

United States Patent [1 1 Scott et a].

[ Apr. 2, 1974 PUNCH PRESS WITH IMPROVED SLUG HANDLING SYSTEM [75]Inventors: William B. Scott, Steward; Roger V.

Sawvell, New Milford, both of 111.

[73] Assignee: W. A. Whitney Corp., Rockfort, ll].

[22] Filed: July 24, 1972 21 Appl. No.: 274,396

3,167,260 1/1965 Gibbons et al.. 83/169 X 2,707,028 4/1955 Burton 83/1003,175,443 3/1965 Kettnich et a]. t 83/100 3,605,551 9/1971 Steward83/171 X Primary ExaminerRoy Lake Assistant Examiner-James F. CoanAttorney, Agent, or FirmWolfe, Hubbard, Leydig, Voit & Osann Ltd.

[5 7] ABSTRACT A punch press includes a binmounted below adie andcommunicating with the latter by way of a passage which directs slugspunched from the workpiece into the bin. A vacuum source is connected toa pipe leading from the bin and draws the slugs through the passage andinto the bin. Mounted beneath a door in the bottom of the bin is a poweroperated conveyor for transporting the slugs away from the bin. The doormay be opened automatically during an interruption in the punchingoperation of the press whereby the slugs are dumped onto theconveyorafter the latter is actuated to carry the slugs away from the bin.During the punching operation, refrigerated air and lubricant are forcedunder pressure into a chamber defined by a stripper housing whichencloses the punch, the lubricant and the air forming a mist for coolingthe punch. As the mist escapes from the chamber through an opening inthe stripper, it is drawn into the die by the vacuum and thus also coolsand lubricates the die. Excess lubricant is drawn through the bin intothe pipe and is separated from the air by a filter at the discharge endof the pipe before the air is exhausted into the atmosphere. I

PATENTED APR 2 I974 SHEEI 2 BF 4 PATENTED 2 I974 SHLEI 3 BF 4 n51 HEREPATENTEDAPR 2 m4 SHEET h 0F 4 4 w M n. m

PUNCH PRES S WITH IMPROVED SLUG HANDLING SYSTEM BACKGROUND OF THEINVENTION This invention relates generally to a punch press and, moreparticularly, to the type of press which includes a system for keepingthe punch and the die from overheating during a punching cycle and forcollecting the slugs punched out of the workpiece. Prior systems usedfor these purposes include a passageway which establishescommunicationbetween the die and a collection bin, there being a vacuum sourceassociated with the bin to draw the press through the passageway andinto the bin. To help cool the punch and die, the vacuum also is used todraw air and lubricant across the punch and into the die. A system ofthis general type is disclosed in GabrielU. S. Pat. No. 3,041,905.

SUMMARY OF THE INVENTION The general object of the present invention isto provide a new and improved vacuum collection system of the abovegeneral character which reduces the amount of work otherwise required bythe punch press operator and thereby shortens the downtime of the punchpress, which serves to better lubricate and cool the punch and the dieand which, at the same time, better cleans the vacuum discharge sothat'the area around the punch press is kept pollution free. One of theprincipal objects of the present invention is to empty the bin and carrytheslugs away to a remote area automatically and preferably as anincident to changing the punch and die or the workpiece thereby to freethe punch press operator to perform other duties. V

A more detailed object is to provide, means in the system for detectinga faulty vacuum seal at the bin during the punching cycle and forshutting down the press to keep the press from operating without propervacuum' in the bin.

Another primary object of the present invention is to keepthe punch andthedie cooler and better lubricated throughthe use of a mist comprisinga mixture of lubricant and refrigerated-air. More particularly, theforegoing is accomplished by confining the mist within a chamber whichalso houses the punch so that the lubricant will collect onvirtually allof the exposed surfaces of the punch to keep the latter betterlubricated as it reciprocates in and out of the housing during apunching cycle so that the normally heated surfaces of the punch arekept substantially cooler. By virtue of the vacuum, the mist also isdrawn from the chamber and into the die thereby cooling and lubricatingthe exposed surfaces of the die.

Theinvention is characterized further by the formation of the chamberwithin a stripper housing, by the provision of a movable bottom wall inthe bin for dumping out the slugs, by the use of a conveyor for carryingthe slugs away fromthe bin, and by the use of BRIEF DESCRIPTION OF THEDRAWINGS FIG. 1' is a fragmentary elevational view of a punch pressembodying the novel features of the present invention and having partsbroken away and shown in cross section for purposes of clarity.

FIG. 2 is an enlarged fragmentary elevational view showing parts of thepress in moved positions from those ofFIG. 1.

FIG. 3 is an enlarged fragmentary elevational view taken along line 33of FIG. 1.

FIG. 4 is an enlarged cross-sectional view taken substantially alongline 4'4 of FIG. 1.

FIG. 5 is an enlarged elevational view taken along line 5-5 of FIG. 1.

FIG. 6 is a cross-sectional view taken substantially along line 6-45 ofFIG. 5.

FIG. 7 is an enlarged fragmentary elevational view taken substantiallyalong line 7-7 of FIG. 1.

FIG. 8 is a combined schematic diagram of the electrical and fluidcircuitry of the present invention.

EMBODIMENT As shown in the drawings'for purposes of illustration, thepresent invention is embodied in a punch press 10 with a fluid-operatedactuator 11 mounted on a horizontal plate 13 and operable to reciprocatea punch 14 into and out of an underlying die 15 to punch holes in anintervening workpiece 16. Herein, the punch is carried on the lower endof a ram 17 which is reciprocated by the actuator while the die issupported directly below the end of the ram within a die shoe 19, thelatter in turn being supported on the bed'20 of the press by a bolsterplate 21. A passage or slug chute 23 extends vertically through the bedand bolster plate from the die opening 22 and communicates with a bin 24mounted on the underside of the bed beneath the die. The slugs(notshown) punched from the workpiece during the performance of a punchingoperation drop through the passage and are collected in the bin.

To help. keep theslugs from possibly hanging up in the die 15 or thepassage 23, the suction side of a vac uum unit 25 is connected to thebin 24 through a pipe 26 to draw the air from the bin. In operation, theslugs are sucked through the die opening 22 and the passage and into thebin. As shown in FIG. 1, the vacuum unit is connected to the pipeadjacent an inlet 27 opening into the back wall 29 of the bin. Moreparticularly, the vacuum unit is of the vortex type wherein air ispulled from the bin and through the pipe as a result of the partialvacuum generated by forcing high pressure air into the unit and outthrough a discharge pipe 32 leading away from the unit. The highpressure air is delivered to the unit through an air line33-communicating between the top of the unit and a pressure source 34(see FIG. 8). Controlling the flow of air through the line is a solenoidvalve 35 connected in the line 33 between the pressure source and thevacuum unit. To keep the slugs from possibly being sucked into the pipe26 when the valve 36 is open, the inlet is covered by a screen 31 (seeFIG. 7).

In the exemplary embodiment, the punching operation 'of the press 10 isnumerically controlled with workpieces 16 being fed automatically intothe press for punching. From time to time, the control program dictateschanging the size of the punch and die set in the press in order topunch holes of different sizes in the workpieces fed into the press.This necessitates an interruption in the punching operation of thepress. Similarly, the punching operation of the press may be interruptedwhen changing from one workpiece to another. In accordance with one ofthe primary aspects of the present invention, provision is made foremptying the bin 24 and carrying the slugs away automatically and as anincident to the interruption in the operation of the punch press 10. Forthis purpose, a door 36 in the bin is opened automatically during theinterruption in the punching operation to dump the slugs onto a conveyor37 disposed below the bin for transporting the slugs away from the bin.Thus, the operator of the punch press is not required to empty the slugsmanually from the bin or to manually carry the slugs away.

In the present instance, the bin 24 (see FIGS. 2 and 3) is generallybox-like in shape with a top wall 39 having a central hole 40 definingthe lowerend of the passage 23. The top wall is somewhat larger in areathan the area outlined by the top edges of the sidewalls 41 of the binthus leaving a peripheral flange 43 around the top of the bin. Bolts 44extending through the flange and into the underside of the bed 20 fastenthe bin to the bed, and a gasket 45 squeezed between the top wall andthe underside of the bed seals the top of the bin against vacuum leaks.Extending around the periphery of the lower edge of the bin is a secondor lower flange 46 and mounted on the forward edge of the lower flangeis the door 36. The latter is supported along its forward end by asubstantially horizontal pivot 49 to move between an open position (FIG.2) and a closed position (FIG. 1) in which the upper or inner surface ofthe door engages a ring gasket 47 affixed to the underside of the lowerflange to seal the bottom of the bin against vacuum leaks. i

To open and close the door 36, the free end of a rod 50 is connected tothe door by a bracket 51 and is reciprocable within an air cylinder 53.The head end of the cylinder is mounted pivotally above the conveyor 37on an angle iron 55 extending between spaced legs 54 depending from thebed 20 of the punch press (see FIGS. 2 and 3). As air is introducedalternatively into the ends of the cylinder through air lines 56, therod advances and retracts to close and open the door 36. The air lines56 connect the opposite ends of the cylinder with the pressure source34, and a solenoid valve 57 (FIG. 8) in the air lines is controlled bysignal from the numerical control to supply air to either end of thecylinder to open or close the door.

In the open position, the door 36 serves as a slide for guiding theslugs onto the conveyor 37, and generally triangular wings 59 (FIG. 2)extending upwardly from opposite side edges of the door keep the slugsfrom falling off the door. In addition, the back end portion 60 of thedoor extends rearwardly beyond the back wall 29 of the bin 24 so that,when the door is pivoted into the open position, the back end of thedoor fits within a chute 61. The latter funnels the slugs onto theconveyor for transportation away from the bin.

Herein, the conveyor 37 is mounted between the legs 54 of the punchpress 10 and is inclined upwardly toward the rear of the press. Moreparticularly, the conveyor comprises a frame 63 (FIG. 1) which issupported between the legs at its lower end by the angle iron 55 andadjacent its upper rear end by a similar angle iron 64. As shown in FIG.1, the upper end of the conveyor extends past the rear of the press andoverhangs a collection basket 65 to dump the slugs in the basket forsubsequent collection. Journaled at the upper and lower ends of theframe are pulleys 66 and 67 about which a flexible belt 69 is trainedfor carrying the slugs to the basket.

To drive the belt 69, an electric motor 70 (FIG. 1) is mounted on theupper end of the frame 63 and is connected to the shaft 71 supportingthe upper pulley 66 on the frame. In the present instance, a signal sentfrom the numerical control to initiate an interruption in the punchingoperation causes actuation of the motor from its normally inactive stateto drive the belt. At about the same time, the solenoid valve 35 (seeFIG. 8) controlling the flow of air to the vacuum unit 25 is de-actuatedto turn off the vacuum in the bin 24. Subsequently, the signal from thenumerical control actuates the valve 57 to retract the rod 50 into thecylinder 53 and thereby pull open the door 36 to dump the slugs onto theconveyor 63. After a predetermined period of time passes, a time delayrelay 73 initially actuated by the signal from the numerical controlde-actuates the motor to shut down the conveyor after the slugs havebeen transported and dropped into the basket 65. Thus, the bin isemptied automatically as an incident to an interruption in the punchingoperation of the press 10 thereby freeing the punch press operator fromthe task of manually emptying the bin.

Advantageously, a limit switch 74 (FIGS. 2 and 7) is mounted on the rearwall 29 of the bin 24 for engagement by the door 36 when the latter isclosed in order to make sure that the door is sealed before actuation ofthe press 10. The switch is connected in the circuitry extending betweenthe numerical control and a control solenoid 75 for the fluid actuator11. When the door is open, the switch also is open and prevents theautomatic cycle of the press by disabling the circuit between thenumerical control and the control solenoid.-

As shown in FIG. 7, when the door is closed, the actuating plunger 76 ofthe switch is depressed to close the circuit between the solenoid 75 andthe numerical control thereby to enable automatic cycling of the punchpress. The switch thus prevents the press from cycling automatically iffor some reason the door is open slightly and not sealed, such as mightoccur should the door be obstructed from closing or forced open underthe weight of the slugs accumulated in the bin during an extended lengthof time between interruptions in the punching operation.

In the exemplary embodiment (see FIG. 1 a stripper 77 is used to stripthe workpiece 16 from the punch 14 when the punch is retracted from theworkpiece during the normal punching cycle of the press 10. As shown, I

the stripper is supported on the lower end of a generally cylindricalhousing 79 which is mounted for vertical adjustment relative to the die15 by a suitable mechanism 80 of the type disclosed in our applicationSer. No. 274,391, filed July 24, 1972 and entitled Punch Press to whichreference may be made for the details of the construction and theoperation of the adjusting. mechanism. As in the aforementionedapplication, the stripper includes a central opening 81 which is shapedand sized to permit the punch to pass downwardly out of the housing witheach downward stroke of the ram 17 to punch a hole in the workpiece.

A door 83 (FIG. 4) forming a half-cylinder portion of the housing 79 ishinged to swing between open and operator of the press to change thepunch and the I stripper 77 as needed for punching different shapes andsizes of holes in the workpiece 16.

Through the use of the numerical control system, the exemplary punchpress 10 may be operated to do contour punching or nibbling wherein theworkpiece is maneuvered under the ram 17 so that a continuous opening ispunched in the workpiece 16 along a predetermined contour by punchingcrescent-shaped slugs from workpiece. In another type of punchingoperation referred to as point-to-point punching, the workpiece may bemaneuvered beneath the ram and punch 14 for punching single holes in theworkpiece. In this latter type of operation, a hole is punched in theworkpiece at one position and theworkpiece is then shifted to a secondposition to be punched again. Upon repeated punching at fast cycle ratessuch as when the numerical control commands either point-to-pointpunching or nibbling, the punch and die tend to become heated and byoverheating may become damaged.

In accordance with another important aspect of the present invention,novel use of the housing 79 is made to keep the punch 14 and die 15better lubricated to reduce wear and better cooling to avoidoverheating. For these purposes, refrigerated air and lubricant areforced under pressure into the chamber 85 and form a cold air mist oflubricant within .the chamber. Confined by the limits of the chamber,themist better lubricates and cools the entire punch 14 to preventoverheating during normal punching operations.

In the present instance, two lines 86 (see FIG. 4) enter the chamber 85through the walls of the stripper housing 79 from a common air linelubricator 87 (FIG. 1). The latter holds a quantity of lubricant in asingle pressure line 89' which communicates between the pressure source34 (See FIG. 8) and the two lines 86. A solenoid 'valve 90 in the line89 is closed and opened in response to commands from the numericalcontrol to prevent and to allow the air to flow into the lubricator topick up the lubricant for spraying into the chamber. Preferably, toconserve the lubricant, the valve 90 is operated in accordance with thepunching mode commanded by the numerical control. For instance, if themode is nibbling, then the valve is set to allow a continual flow of airto the lubricator. If, however, the mode is point-to-point, the valve isoperated normally to open and close during repositioning the workpieceremaining open for a predetermined period of time as the workpiece 16 isbeing moved from point to point.

As shown in FIGS. 1 and 4, the two lubricant lines 86, enter the housing79 at positions spaced from each other at an included angle relative tothe central axis of i sprayed into the chamber so that all exposedsurfaces of the punch are kept well lubricated for punchmg.

To cool the punch, a cold air hose 93 enters the chamber 85 through thehousing 79 between the two nozzles 91 at approximately the same verticalposition above the stripper 77 as the nozzles. More particularly, thenozzle 92 of the cold air hose is located at a position angularly spacedat about 70 degrees from the closest nozzle 91. Also, the nozzle 92 isslanted downwardly toward the stripper at an angle similar to that ofeach of the nozzles 91 to direct the cold air onto the punch 14 and tohelp impart the swirling flow to the mist which includes both therefrigerated air and the sprayed lubricant.

The inlet end of the cold air hose 93 connects with a refrigeration unit94 which is mounted on the punch press 10 behind the fluid actuator 11.An air line 95 (see FIG. 8) connected between the refrigeration unit andthe pressure source 34 delivers air under pressure to the unit forcooling. Asolenoid valve 96 connected in the line 95 between therefrigeration unit and the source is opened and closed on commandfromthe numerical control to permit the flow of refrigerated air throughthe hose and into the chamber 85 for cooling the punch during thepunching operation.

In addition to keeping the punch 14 from overheating, the combined coldair and lubricant escaping from thehousing 79 also cools and lubricatesthe die 15. Upon passing through the opening 81 in the stripper 77, themist is captured by the vacuum in the die opening 22 and is drawn acrossthe exposed surfaces of the die to keep such surfaces from overheatingand experiencing excessive wear.

' By virtue of the combined action of the chamber 85 in comfining themist around the lower end of the ram 17 and of the vacuum in drawing theescaping mist into the die 15, the present arrangement alsoadvantageously avoids pollution of the immediate punching area with thelubricant during the actual punching operation. The excess lubricantwhich passes through the die 15 is sucked through the bin 24 and intothe pipe 26 by the vacuum unit 25. To avoid pollution of the immediatepunching area when the door 85 is opened to change the punch 14,provision is made for purging the chamber 85 of the mist prior toopening the chamber 85 through the wall of the housing 79 adjacent theadjusting mechanism 80. The conduit directs clean air into the chamberwhen the valve is opened in response to a command from the numericalcontrol to purge the chamber of the polluting mist.

To prevent lubricant drawn through the vacuum unit 25 from-beingexhaustedback into the air, a filter box 97 is connected at thedischarge end 98 of the pipe 32 to separate the lubricant from theexhaust air. As shown in FIG. 1, the filter box is mounted on theback ofthe press 10 with the discharge end of the pipe connected to the frontofthe box to direct the exhaust air into a lower chamber 99 (see FIGS. 5and 6) within the box; Two industrial-type filters 100 define the top ofthe chamber and are formed of steel mesh toseparate dirt and grease fromthe exhaust air. A curved hood 101 on the top of the box directs thefiltered air back into the atmosphere through a generally rectangularopening 103 in the front side of the box.

In the exemplary embodiment, command signals from the numerical controlare used to initiate the operation of all the solenoid valves 35, 57,90, 96 and 105 as well as the operation of the conveyor motor 70. Thus,for instance, upon receiving the command to change the punch and dieset, the solenoid valves 90 and 96 are closed to stop the flow ofrefrigerated air and lubricant into the housing 79. At the same time,the solenoid valve 105 is opened to purge the chamber 85 of lingeringmist. Upon receipt of a second command, the valves 35 and 105 are closedto turn off the vacuum and the purge air. Coincidentally therewith, theconveyor motor 70 is actuated to drive the belt 69 and, after a briefdelay, a third command causes the valve 57 to operate the cylinder 53 toopen the bin door 36 to dump the slugs onto the moving belt. The timedelay relay 73 keeps the motor running long enough for slugs to bedelivered into the basket 65 and then the motor is shut off to stopfurther movement of the belt. Once the change of the punch and die setis completed, the operator depresses a cycle start button (not shown)initiating a second set of command signals to reverse the solenoidvalves 57, 35, 90 and 96. If the bin door seals closed properly to holdthe vacuum, the punching cycle is ready to continue after the solenoidvalves assume their normal operating positions.

While the present invention has been described herein as used in a punchpress with numerical control system, it will be appreciated that theunique features of the present invention may be employed with equaladvantage in a manually operated punch press. In fact, this isexemplified in the present punch press control arrangement through theuse of a manual control 106 (FIG. 8) whereby the numerical controlsystem may be overridden by the punch press operator to produce signalsto simulate certain of the commands of numerical control. In particular,the manual control may be used to energize the time delay relay 73 tostart the conveyor 37 and to operate the valve 57 to open the bin door36.

We claim as our invention:

1. A punch press having a vertically reciprocable punch adapted to coactwith an underlying die to punch holes in an intervening workpiece, saidpress including a bin disposed below said die to collect the slugspunched from the workpiece, apassage communicating between the die andthe bin, a vacuum source connected with said bin to draw the slugsthrough the passage and into the bin, 2. door mounted on the bin to moveto an open position to enable the removal of the slugs from the bin, aconveyor disposed below the door to carry the slugs away from the bin,and means for automatically opening said door to dump the slugs onto theconveyor during an interruption in the punching operation of said press.

2. A punch press having a vertically reciprocable punch adapted tovcoact with an underlying die to punch holes in an intervening workpiece,said press including a bin disposed below said die to collect the slugspunched from the workpiece, a passage communicating between the die andthe bin, a vacuum source having a suction pipe and a discharge pipe,said suction pipe being connected to the bin to draw the slugs throughthe passage and into the bin, a door mounted on the bin to move to anopen position to enable the removal of the slugs from the bin, aconveyor disposed below the door to carry the slugs away from the bin,power means for operating said conveyor, mechanism for opening said doorto dump the slugs onto the conveyor, and signal responsive meansoperable to disable the vacuum source, to actuate the conveyor powermeans and to actuate said door mechanism to open the door and dump theslugs on the conveyor for transportation away from the bin.

3. A punch press as defined by claim 2 including a limit switch mountedon said bin and operable to detect when said bin door is openedpartially and to produce an electrical signal in response thereto.

4. A punch press as defined by claim 3 wherein said door mechanismincludes a fluid-actuated cylinder, a rod extending from said cylinder,said rod and said cylinder being connected to said door whereby thelatter is closed and opened by advancing and retracting said rod withinsaid cylinder, and said signal responsive means being operable toactuate said cylinder to retract the rod and open the door.

5. A punch press with a vertically reciprocable ram mounted on a frame,a punch carried on the lower end of said ram and adapted to coact withan underlying die to punch holes in an intervening workpiece, said pressincluding a bin mounted on said frame below said die to collect theslugs punched from the workpiece, a passage communicating through theframe between the die and the bin, an exhaust pipe with an inlet endconnected to the bin, a vacuum source connected to the pipe to draw theslugs through the passage and into the bin, a door mounted on the bottomof the bin to pivot about a substantially horizontal axis between anopen position and a closed position, said door sealingly engaging thebin when in said closed position, a belt-type conveyor disposed belowthe door to carry the slugs away from the bin, power means for operatingsaid conveyor, mechanism for opening said door to dump the slugs ontothe conveyor during an interruption in the punching operation of thepress, said mechanism including a fluid-actuated cylinder and rodconnected between said door and said frame to close and open said doorby advancing and retracting said rod within the cylinder, and meansoperable during said interruption to disable said vacuum source, toactuate the conveyor power means and to actuate said cylinder to openthe door and dump the slugs on the conveyor for transportation away fromthe bin.

6. A punch press having a vertically reciprocable punch adapted to coactwith an underlying die to punch holes in an intervening workpiece, saidpress including a bin disposed below said die to collect the Slugspunched from the workpiece, a passage communicating between the die andthe bin, a vacuum source connected with said bin to draw the slugsthrough the passage and into the'bin, a door on the bin for movement toan open position enabling removal of the slugs from the bin, a conveyordisposed below the door to carry the slugs away from the bin, means forautomatically opening said door to dump the slugs on the conveyor duringan interruption in the punching operation of said press, a housingdisposed around the punch and defining an enclosed chamber, and meansfor forcing refrigerated air and lubricant under pressure into saidchamber to form a mist around the punch for lubricating and cooling thelatter, said mist also cooling and lubricating the die by being forcedby said means out ofthe chamber through an opening in the bottom of saidhousing to be drawn across the exposed surfaces of said die by saidvacuum.

7. A punch press having a vertically reciprocable ram carrying a'punchadapted to coact with an underlying die to punch holes in an interveningworkpiece, said press including a bin disposed below said die to collectthe slugs punched from the workpiece, a passage communicating betweenthe die and the bin, a vacuum source having a suction pipe and adischarge pipe, said suction pipe being connected to draw the slugsthrough the passage and into the bin, a sealed door in the'bin andadapted to be opened toremove the slugs from the bin, a conveyordisposed below the door to carry the slugs away from the bin, powermeans for operating said conveyor, mechanism for opening said door todump the slugs onto the conveyor during an interruption in the punchingoperation of said press, means operable during said interruption todisable the vacuum source, to actuate the conveyor power means and toactuate said door mechanism to open the door and dump the slugs on theconveyor for transportation away from the bin, a housing defining anenclosed chamber disposed around the punch at the lower end of the ram,means for forcing refrigerated air into said chamber, means for forcinglubricant into said chamber to form a mist of cold air and lubricantaround the punch for lubricating and cooling the latter, said mist alsocooling and lubricating the die by being forced out of the chamberthrough an opening in the bottom of the housing to be drawnacross theexposed surfaces of said die and into the bin by said vacuum, and afilter connected to said discharge pipe to separate the lubricant fromthe air before the air is exhausted into the atmosphere.

8. A punch press having a reciprocable ram carrying a punch adapted tocoact with an underlying die to punch a hole in an interveningworkpiece, said press including a housing defining a substantiallyenclosed chamber disposed around said punch and having a lower openingfor admitting said punch therethrough to punch a hole in said workpiece,and means for forcing refrigerated air and lubricant into said chamberunder pressure to form a mist of the lubricant around the also forcingthe mist out of said lower opening to cool said underlying die.

' 9. A punch press with a vertically reciprocable ram mounted on aframe,a punch carried on the lower end of said ram and adapted to coact withan underlying die to punch a hole in an intervening workpiece, saidpress including a housing mounted on said frame around the lower end ofsaid ram and defining a substantially enclosed chamber around saidpunch, said housing having a bottom plate with a central opening thereinto admit said punch therethrough to punch a hole in said workpiece, andmeans for forcing refrigerated air and lubricant into said chamber underpressure to form a mist of the lubricant around the punch forlubricating and cooling the punch and for forcing the mist out of saidhousing through said opening and toward said die, an exhaust pipe withan inlet end communicating with said die, a vacuum source connected withsaid pipe to draw the lubricant into the die to lubricate and cool theexposed surfaces of the die and to exhaust the'excess lubricant throughthe pipe.

10. A punch press as defined by claim 9 including means for purging saidchamber of said mist prior to changing punches on the end of the ram toavoid releasing the mist into the atmosphere around the punch press.

11. A punch press as defined by claim 10 in which said purging meansinclude an air hose communicating with thetop of said chamber throughsaidhousing and a pressure source for forcing clean air through saidhose to purge the chamber of lubricant by driving the mist out of thechamber through the opening.

12. A punch press as defined by claim 11 wherein said means for forcingrefrigerated air and lubricant into the chamber includes two nozzleslocated adjacent the sidewalls of said housing at angularly spacedpositions from each other to direct the lubricant in generally opposingdirections past opposite sides of the central axis of the ram to createa swirling of the mist in the chamber. 7

13. A punch press as defined by claim 10 including a filter connected tothe outlet of said pipe to separate the lubricant from the air beforethe air is exhausted into the atmosphere.

1. A punch press having a vertically reciprocable punch adapted to coactwith an underlying die to punch holes in an intervening workpiece, saidpress including a bin disposed below said die to collect the slugspunched from the workpiece, a passage communicating between the die andthe bin, a vacuum source connected with said bin to draw the slugsthrough the passage and into the bin, a door mounted on the bin to moveto an open position to enable the removal of the slugs from the bin, aconveyor disposed below the door to carry the slugs away from the bin,and means for automatically opening said door to dump the slugs onto theconveyor during an interruption in the punching operation of said press.2. A punch press having a vertically reciprocable punch adapted to coactwith an underlying die to punch holes in an intervening workpiece, saidpress including a bin disposed below said die to collect the slugspunched from the workpiece, a passage communicating between the die andthe bin, a vacuum source having a suction pipe and a discharge pipe,said suction pipe being connected to the bin to draw the slugs throughthe passage and into the bin, a door mounted on the bin to move to anopen position to enable the removal of the slugs from the bin, aconveyor disposed below the door to carry the slugs away from the bin,power means for operating said conveyor, mechanism for opening said doorto dump the slugs onto the conveyor, and signal responsive meansoperable to disable the vacuum source, to actuate the conveyor powermeans and to actuate said door mechanism to open the door and dump theslugs on the conveyor for transportation away from the bin.
 3. A punchpress as defined by claim 2 including a limit switch mounted on said binand operable to detect when said bin door is opened partially and toproduce an electrical signal in response thereto.
 4. A punch press asdefined by claim 3 wherein said door mechanism includes a fluid-actuatedcylinder, a rod extending from said cylinder, said rod and said cylinderbeing connected to said door whereby the latter is closed and opened byadvancing and retracting said rod within said cylinder, and said signalresponsive means being operable to actuate said cylinder to retract therod and open the door.
 5. A punch press with a vertically reciprocableram mounted on a frame, a punch carried on the lower end of said ram andadapted to coact with an underlying die to punch holes in an interveningworkpiece, said press including a bin mounted on said frame below saiddie to collect the slugs punched from the workpiece, a passagecommunicating through the frame between the die and the bin, an exhaustpipe with an inlet end connected to the bin, a vacuum source connectedto the pipe to draw the slugs through the passage and into the bin, adoor mounted on the bottom of the bin to pivot about a substantiallyhorizontal axis between an open position and a closed position, saiddoor sealingly engaging the bin when in said closed position, abelt-type conveyor disposed below the door to carry the slugs away fromthe bin, power means for operating said conveyor, mechanism for openingsaid door to dump the slugs onto the conveyor during an interruption inthe punching operation of the press, said mechanism including afluid-actuated cylinder and rod connected between said door and saidframe to close and open said door by advancing and retracting Said rodwithin the cylinder, and means operable during said interruption todisable said vacuum source, to actuate the conveyor power means and toactuate said cylinder to open the door and dump the slugs on theconveyor for transportation away from the bin.
 6. A punch press having avertically reciprocable punch adapted to coact with an underlying die topunch holes in an intervening workpiece, said press including a bindisposed below said die to collect the slugs punched from the workpiece,a passage communicating between the die and the bin, a vacuum sourceconnected with said bin to draw the slugs through the passage and intothe bin, a door on the bin for movement to an open position enablingremoval of the slugs from the bin, a conveyor disposed below the door tocarry the slugs away from the bin, means for automatically opening saiddoor to dump the slugs on the conveyor during an interruption in thepunching operation of said press, a housing disposed around the punchand defining an enclosed chamber, and means for forcing refrigerated airand lubricant under pressure into said chamber to form a mist around thepunch for lubricating and cooling the latter, said mist also cooling andlubricating the die by being forced by said means out of the chamberthrough an opening in the bottom of said housing to be drawn across theexposed surfaces of said die by said vacuum.
 7. A punch press having avertically reciprocable ram carrying a punch adapted to coact with anunderlying die to punch holes in an intervening workpiece, said pressincluding a bin disposed below said die to collect the slugs punchedfrom the workpiece, a passage communicating between the die and the bin,a vacuum source having a suction pipe and a discharge pipe, said suctionpipe being connected to draw the slugs through the passage and into thebin, a sealed door in the bin and adapted to be opened to remove theslugs from the bin, a conveyor disposed below the door to carry theslugs away from the bin, power means for operating said conveyor,mechanism for opening said door to dump the slugs onto the conveyorduring an interruption in the punching operation of said press, meansoperable during said interruption to disable the vacuum source, toactuate the conveyor power means and to actuate said door mechanism toopen the door and dump the slugs on the conveyor for transportation awayfrom the bin, a housing defining an enclosed chamber disposed around thepunch at the lower end of the ram, means for forcing refrigerated airinto said chamber, means for forcing lubricant into said chamber to forma mist of cold air and lubricant around the punch for lubricating andcooling the latter, said mist also cooling and lubricating the die bybeing forced out of the chamber through an opening in the bottom of thehousing to be drawn across the exposed surfaces of said die and into thebin by said vacuum, and a filter connected to said discharge pipe toseparate the lubricant from the air before the air is exhausted into theatmosphere.
 8. A punch press having a reciprocable ram carrying a punchadapted to coact with an underlying die to punch a hole in anintervening workpiece, said press including a housing defining asubstantially enclosed chamber disposed around said punch and having alower opening for admitting said punch therethrough to punch a hole insaid workpiece, and means for forcing refrigerated air and lubricantinto said chamber under pressure to form a mist of the lubricant aroundthe punch for lubricating and cooling the latter, said means alsoforcing the mist out of said lower opening to cool said underlying die.9. A punch press with a vertically reciprocable ram mounted on a frame,a punch carried on the lower end of said ram and adapted to coact withan underlying die to punch a hole in an intervening workpiece, saidpress including a housing mounted on said frame around the lower end ofsaid ram and defining a substantially enclosed chamber around saidpunch, said hoUsing having a bottom plate with a central opening thereinto admit said punch therethrough to punch a hole in said workpiece, andmeans for forcing refrigerated air and lubricant into said chamber underpressure to form a mist of the lubricant around the punch forlubricating and cooling the punch and for forcing the mist out of saidhousing through said opening and toward said die, an exhaust pipe withan inlet end communicating with said die, a vacuum source connected withsaid pipe to draw the lubricant into the die to lubricate and cool theexposed surfaces of the die and to exhaust the excess lubricant throughthe pipe.
 10. A punch press as defined by claim 9 including means forpurging said chamber of said mist prior to changing punches on the endof the ram to avoid releasing the mist into the atmosphere around thepunch press.
 11. A punch press as defined by claim 10 in which saidpurging means include an air hose communicating with the top of saidchamber through said housing and a pressure source for forcing clean airthrough said hose to purge the chamber of lubricant by driving the mistout of the chamber through the opening.
 12. A punch press as defined byclaim 11 wherein said means for forcing refrigerated air and lubricantinto the chamber includes two nozzles located adjacent the sidewalls ofsaid housing at angularly spaced positions from each other to direct thelubricant in generally opposing directions past opposite sides of thecentral axis of the ram to create a swirling of the mist in the chamber.13. A punch press as defined by claim 10 including a filter connected tothe outlet of said pipe to separate the lubricant from the air beforethe air is exhausted into the atmosphere.